Fill up Geoshape question by formulas

[KaiPongNg]

Hi,

Anyone has idea to assign value (answer) to a Geoshape (question).

An ODK validation error occurred. On the other hand, any advice or tool able to get the detail of message? It didn't show in Connect's error log.

I just put a JS function to return a ring geometry. 

If I put the string to "Default" of the Geoshape, the map able to display on the survey form.

Thanks,

Pong